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3 6 00 A, 

THE 

WATERPROOFING 

OF 

STRUCTURES 



WITH SPECIAL REFERENCE 
TO SUBLEVEL CONSTRUCTION, 
THE ENVELOPE METHOD 
AND THE APPLICATION OF 

"TUNALOID" 



J. A. & W. BIRD & COMPANY 

34 and 35 INDIA STREET 
BOSTON, MASS. 

NEW YORK, CHICAGO, NEW ORLEANS, MONTREAL 



^ 



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Copyrighted, 1910 

J. A. & W. BIRD & CO. 

Boston, Mass. 



fl-Wy 



OXFORD-PRINT BOS I ON U.S.A. 



©CI.A259125 



The Waterproofing 
of Structures 



A PRIMARY function of practically every type of struc- 
ture is to prevent the entrance of moisture. As a rule, 
those which extend above the surface have merely to shed the 
rain. The materials of construction themselves, roofing in its 
various forms, paint or plaster, serve effectually to meet the 
requirements. The surfaces are readily accessible for repairs, 
and except where water pockets are formed there is compara- 
tively little difficulty in making such a structure moisture 
proof. An exception exists in the case of such structures as 
steel and reinforced concrete bridges exposed to the weather 
and subject to vibration, where extremes of temperature have 
a serious effect in causing expansion and contraction, and 
where water may stand for considerable periods. 

But below surface level the conditions are changed, and the 
difficulties vastly increased. In its natural state earth is always 
moist. It is the recipient of all the rain that falls. In the case 
of open sand and gravel, it sinks rapidly to lower levels, which 
in clayey soils or in ledge formations remain pocketed for long 
periods relatively near the surface. 

In the sublevel structure like the ordinary house cellar, with 
its bottom seldom more than eight or ten feet below the sur- 
face, there is seldom much difficulty in preventing the entrance 
of water. The pressure due to its head is comparatively slight 
and well laid walls, or concrete foundations, with proper sub- 
drainage conducted to a point of free discharge usually insure 
freedom from all annoyance. 

But when an excavation is made in springy ground or its 
bottom is below the level of nearby water in lake, river, or 
sea, percolation inevitably results. The open space furnishes 
a ready receptacle toward which the water naturally flows under 

l 



THE WATERPROOFING OF STRUCTURES 

this pressure due to its depth. There being no lower level 
to which it may be drained it becomes imperative that the 
excavated area, surrounded as it may be by such a body of 
water, should be completely enveloped in an absolutely imper- 
vious shield. Such a shield is not provided by the ordinary 
foundation. 

With the recent rapid advance in building methods, and the 
growing values of sublevel spaces in large communities, the 
problem of securing absolute freedom from moisture within such 
structures has become serious and increasingly difficult of solu- 
tion. At depths of 30 to 40 feet water pressures may rise to 
over a ton per square foot of surface. Hydrostatic pressures 
at different depths are given in the accompanying table. 

HYDROSTATIC PRESSURES. 



Hydrostatic 
Head Feet 


Pressure 
Per Square 
Inch Lbs. 


Pressure 
Per Square 
Foot Lbs. 


0.5 
1.0 

2.0 


0.21 
0.43 
0.86 


31.2 

62.5 

125.0 


3.0 


1.30 


187.5 


4.0 


1.73 


250.0 


5.0 
6.0 
8.0 


2.17 
2.60 
3.47 


312.5 
375.0 
500.0 


10.0 


4.34 


625.0 



Hydrostatic 
Head Feet 



| Pressure 
Per Square 
Inch Lbs. 



12.0 
15.0 
20.0 
25.0 
30.0 
40.0 
60.0 
80.0 
100.0 



5.21 
6.51 
8.68 
10.85 
13.02 
17.36 
26.04 
34.72 
43.40 



Pressure 
Per Square 
Foot Lbs. 



750.0 
937.5 
1250.0 
1562.5 
1875.0 
2500.0 
3750.0 
5000.0 
6250.0 



So far as the stability of the structure itself is concerned 
such pressures are easily resisted by the thickness of the walls 
necessary to support the superstructure and withstand the 
lateral pressure of the earth. In the tunnel or subway such 
resistances may be provided with engineering certainty and 
usually without complicated design. In a word, deflection and 
destruction may be readily prevented. 

2 



THE WATERPROOFING OF STRUCTURES 

But to prevent the entrance of water is a far more difficult 
problem. In fact the successful construction of a substructure 
in any way exposed to external water ultimately depends upon 
the perfection of the waterproofing method employed. Once 
built, its exterior is practically inaccessible. Hence, an ounce of 
prevention is most emphatically worth more than a pound of 
cure. 

All structural materials used for foundations or similar pur- 
poses are of necessity hard, rigid and inelastic. Though more 
or less impervious through their substance, they usually present 
opportunity for passage of water at their joints, or through 
cracks which because of their inelastic nature are almost certain 
to develope. 

Brick, which is exceptionally porous, is seldom encountered 
in large structures where the waterproofing problem assumes 
distinct magnitude. Broken or cut stone which formerly pre- 
vailed as a substructural material, presents in the completed 
wall no end of possibilities for inward leakage at the multitu- 
dinous joints. But concrete has now become so universal as a 
foundation building material that all others are of secondary 
importance. 

If concrete were a homogeneous material, always of the 
same composition and characteristics thoroughout, the question 
of its permeability might be readily and conclusively settled. 
But composed as it is of various aggregates, — cement, sand 
and gravel or broken stone, — each differing greatly in its indi- 
vidual quality, mixed in a wide range of proportions, and with 
varying degrees of thoroughness, concrete becomes merely a 
generic name. The laboratory sample can never be more 
than an average of the material in the completed structure, 
which in itself may vary widely in different portions. 

While it may be possible to render a small mass of con- 
crete entirely impervious to water it is still an open question 
whether a multitude of such small masses may be so united 
that the entire body will always be impermeable. 



THE WATERPROOFING OF STRUCTURES 

It is a condition and not a theory with which the engineer 
is confronted. To secure impermeability, every particle of 
sand must be coated with cement and every particle of stone 
must be so surrounded with this cement and sand that the 
stones and the sand grains do not come in actual contact but 
are always separated by films of cement which completely fill 
all voids. Such perfection is entirely dependent upon the skill 
with which the ingredients are mixed and placed in position 
and this in turn determines the cost of the structure. 

It has been generally considered that the cheapest labor was 
sufficient for the mixing of concrete and that to reduce its per- 
meability it was only necessary to use pienty of cement. But 
with such unskilled labor, no matter what the richness of the 
concrete, there is always the probability of improper setting 
and the imperfect bonding of portions of the work laid at 
separate intervals. 

Although the quality of the work may obviously be improved 
by the employment of higher paid men, there still remains the 
possibility of imperfection. It is this possibility always present 
in such construction which, aside from other causes, renders 
imperative the employment of independent means for absolutely 
insuring the impermeability of the entire structure. 

As a rule experiments upon permeability give somewhat 
uncertain results, and it is not unusual to find blocks of the 
same concrete which although treated in an identical manner, 
permit very different quantities of water to filter through them. 
In a general way it has been determined that the permeability 
of concrete diminishes as the proportion of cement is increased. 
When the composition itself is varied a wide variation in water- 
tightness is usually the result. 

What is true of composition is likewise true of thickness. 
Because of variations in proportions and methods of laying it is 
impossible to specify definite thicknesses of concrete to prevent 
percolation under different heads of water. Rain water under 
a head of two or three inches has been known to percolate 
through a four foot wall of excellent concrete and dry consist- 

4 



THE WATERPROOFING OF STRUCTURES 

ency, while a three inch wall under four feet head of water has 
proven perfectly tight. These facts only emphasize the uncer- 
tainties prevailing in so called water-tight concrete construction. 

Continuous tests have shown that ordinary seepage through 
concrete usually decreases with time. This has been attributed 
to the gradual stopping of the pores by the carbonates of lime 
which result from the attack of the cement by lime-carrying 
water passing through it and its subsequent exposure to the 
atmosphere. These efflorescenses tend to solidify the mortar 
and form an outer coating, and are the material cause of the 
gradual decrease in percolation of water. It is but natural 
therefore that hydrate of lime should be suggested as an ingre- 
dient of the concrete to be introduced at the time of mixing. 
This like many other materials, such as sulphate of alumina, 
soap, alum, or metallic stearates has been made the basis of 
compounds designed to be incorporated with the concrete for 
making it water-tight. These act in various ways, and in the 
case of many so called waterproof compounds of unspecified 
composition put together without regard to chemical principles, 
the effect upon the endurance of the concrete is absolutely 
unknown. In some cases they have been found to contain 
a large proportion of inert substances which interfere with 
the nominal setting of the concrete and materially decrease 
its strength while exerting a negative influence upon its 
permeability. 

But aside from these facts success in the use of an otherwise 
proper ingredient always depends upon the thoroughness with 
which it is incorporated into the concrete. Even distribution 
throughout the mass is absolutely necessary. Here again is 
the ever present possibility of imperfect work, which leaves 
actual service as the only proof that it has been done properly. 
To many this risk appears too great to be undertaken and as 
a consequence, a waterproofing method is adapted which per- 
mits of inspection during its application. 

But after all is said and done the absolute impermeability of 
the material of the structure may count for little in its ultimate 

5 



THE WATERPROOFING OF STRUCTURES 

ability to prevent the admission of water from the surrounding 
soil. Being of necessity an inelastic material, ruptures in the 
form of minute, hardly perceptible cracks or more clearly 
defined crevices are always liable to occur under strains induced 
by temperature changes, settlement, warping, etc. The elas- 
ticity of concrete, such as it is, varies with its composition and 
the size of the stone. But in no sense can concrete be con- 
sidered an elastic material. Its co-efficient of expansion per 
degree Fahrenheit ranges from .000005 to .000008 according 
to the mixture. The expansion averages about the same as for 
iron or steel which therefore proves a suitable material for 
reinforcement. The actual variation in dimensions is better 
realized by considering 100 feet in length of concrete and a 
temperature change of 100 degrees F. ; the change in length 
is then three quarters of an inch. The same increase in 
temperature will increase by .40 cubic foot a 10 foot cube of 
concrete. 

Although an ordinary structure 50 or 60 feet in any dimen- 
sions can, with careful attention to all details, be constructed to 
take up temperature stresses without the introduction of re- 
inforcement, it is still always subject to possible minute rupture 
or to such imperfections in the bonding or joining of successive 
batches of concrete as will permit of the passage of water. It 
is always possible that channels may be established through 
which the water may percolate. 

In larger structures, iron or steel reinforcement will insure 
general provision for expansion and contraction through cracks 
confined by the construction to certain definite places. But im- 
perfections are still possible in the balance of the work. The 
cracks may be treated as joints to be made water-tight by 
special means, with the possibility, however, of ultimate leak- 
age if the material employed is directly and rigidly attached 
to the concrete on either side and obliged to move with it. 

Manifestly then, while concrete may of itself in the case of 
laboratory specimens and small batches mixed with special care 
prove practically impervious, in large masses mixed perchance 



THE WATERPROOFING OF STRUCTURES 

by unskilled labor there must always be an element of doubt 
which can only be removed by the proof of water-tightness in 
actual service. Such tightness is not to be measured by the 
absence of dripping water but by absolute freedom from the 
least appearance or feeling of moisture upon the inner surface. 
Though such a condition may prevail in a structure shortly 
after its completion, the stresses which always exist may 
eventually find relief long after in the form of local ruptures. 
In a word there is always risk of leakage. 

The method whereby it is undertaken to render concrete 
impervious by the introduction of an ingredient is manifestly 
so simple that had it proven as economical, practical and effec- 
tive for substructural as for superstructural work there would 
be no reason for the consideration of any other methods. But 
the fact that it is not generally employed and that other meth- 
ods prevail is manifestly the best evidence of their superiority. 

Such are those concerned with some external application to 
the surface or the enveloping of the entire structure in a practi- 
cally independent pliable waterproof envelope or shield. 

Surface coatings are as old as concrete itself. For centuries 
neat cement has been used in the form of a wash or a trowelled 
grout. Under the conditions previously prevailing, where 
great depth of substructure did not exist and absolute imper- 
meability was not necessary, such simple means have appeared 
sufficient. In similar manner asphalt or coal tar pitch has been 
applied hot as protection against the passage of water. For 
years Sylvester's solution of alum and soap has been applied 
in many coats with varying success. 

Concrete surfaces have been impregnated with paraffine, 
paint in a hundred forms has been used, enamels and the like 
have been brought to notice. In many cases they have proved 
practical and efficient for the waterproofing of structures above 
the surface but absolutely useless for those below. It is emi- 
nently logical that any protection whether applied directly to 
the surface or merely enveloping it should be upon the water 
side and that it should serve to prevent contact of water with 



THE WATERPROOFING OF STRUCTURES 



that surface. Once admitted to contact with the concrete the 
water will search out and follow every channel, no matter how 
minute, that leads through its substance. In the case of re- 
inforced concrete it is urgently necessary that the steel should 
be absolutely protected from moisture. This certainly cannot 
be done unless the entire structure is completely and effectively 
enveloped in a waterproof shield. But under the ordinary 
conditions of construction the application of any coating direct 
to the outside of a completed wall of a substructure entails the 
excavation of an external area sufficient for working space. 
The cost of such excavation aside from other considerations is 
alone sufficient reason for considering such a method impracti- 
cable, particularly at any great depth. Where the surface is 
exposed above ground level during construction it is of course 
easy to apply any form of waterproofing. 

It is but natural that because of the ease of application coat- 
ings should be tried upon the inner rather than the outer 
surfaces of structures below ground level. But this always 
leaves water free to exert its pressure to push off the coating 
rather than bind it faster to the surface as would be the case 
if it was applied upon the outside. It is this fact that 
has rendered so many forms of inside coating absolutely 
useless. 

The only possibility of opposing a reasonably effective stop 
to the water by an inside application lies in making it of ample 
thickness and bonding it effectually to the existing concrete. 
Waterproofing cement in various forms has been tried under 
these conditions. In one of the most successful forms it com- 
bines with the good qualities of a first class Portland Cement 
the power of repelling water. It is usually applied in a coating 
about 5g of an inch thick but requires a special sand for its 
mixing and especially skilled labor in its manipulation. 

Its success depends primarily upon its adherence to the wall, 
but being deficient in elasticity the shrinkage cracks on re- 
inforced concrete are sufficiently large to fracture the coating 
and render it of questionable value. 



THE WATERPROOFING OF STRUCTURES 

From this somewhat critical discussion of waterproofing 
methods it is clearly manifest that the integrity of any material 
or method lies not in itself but in the concrete or other struc- 
tural material with which it is incorporated or to which it is 
applied. Variety in material and mixtures as well as lack of 
skill in the work always leave its character in doubt. So long 
as the thoroughly made wall or floor remains intact there is a 
possibility that some of the better methods of waterproofing 
already mentioned may prove successful, but the moment the 
slightest fracture occurs trouble begins if water be present. 

Theoretically a substructure may be made watertight by such 
means, but practically there always exists the possibility of 
imperfection and failure. In the present state of the building 
art and doubtless for years to come this possibility cannot be 
overlooked and definite steps must be taken to insure against 
the effect of its occurrence. Such insurance can take only one 
practical form, namely the provision of an exterior pliable 
waterproof envelope or shield composed of materials unaffected 
by water, or other matter in the soil, durable under all con- 
ditions and free from the influence of movement on the part 
of the structure itself. 

A shield or envelope to fulfil these conditions must consist 
of more than a mere coating applied to the outer surface of the 
structural material. No matter how thick an application of 
asphalt, cement or mastic compound of both materials may be, 
its resistance to rupture is by no means increased by such 
thickness. So long as it maintains a bond with the wall to 
which it is applied, and this is always necessary, it must expand 
or contract, twist or settle with that wall. Seldom does such a 
coating have the same elasticity or the same coefficient of expan- 
sion as the structure to which it is applied. Hence it may crack 
even when the wall does not and is practically certain to when 
it does. In a word, such a surface coating is in no sense a 
separate envelope but an integral part of the wall, and hence 
fails to fulfil the first requirement of the envelope method, i. e. 
opportunity for independent movement. 



THE WATERPROOFING OF STRUCTURES 



The true envelope or shield must be free to move or remain 
stationary with practical independence of the structure, it must 
be a shell or shield which entirely, or so far as may be neces- 
sary, surrounds the structure and prevents all water from 
coming in contact with it. 

In its most practical and economical form such an envelope 
is composed of a series of layers or plies of a suitable fabric 
cemented together with a waterproofing compound. Above 
all the fabric must of itself be waterproof so that each individual 
layer may serve as an independent barrier to the passage of 
water, while the intermediate coatings of cementing compound 
must individually supplement this waterproofing quality and 
collectively bind the series of plies into a pliable sheet of sub- 
stantial thickness. The particular attributes of a suitable felt 
and a satisfactory cement are hereinafter discussed. 

As with all materials of this character their successful use 
depends largely upon the care with which they are applied. 
A primary requirement with all waterproofing laid in layers of 
fabric is that the edges shall overlap so that as sheet after sheet 
is laid side by side these laps shall be uniform and the number 
of thicknesses be the same in all parts. It is also necessary that 
these sheets as they are successively laid shall be securely ce- 
mented to each other, that there shall be no air pockets causing 
separation of the sheets and no uncoated surfaces, the spaces 
between which might furnish channels for the passage of water. 

Beyond such general requirements for satisfactory work no 
set specifications can be established. Each class of work re- 
quires its own particular treatment as regards material and 
method of application. The general methods employed with 
various types of structures may however be briefly considered 
here, although discussed at length hereafter. 

The development of the steel bridge with gravel or macadam 
filled road way for vehicles or similar bed for railroad tracks 
has led to a demand for special protection for the steel surfaces 
beneath the roadway or track. Hidden as thev are these sur- 
faces must be so thoroughly protected from moisture that 

10 



THE WATERPROOFING OF STRUCTURES 

deterioration will be almost impossible. The futility of relying 
on coatings or coverings of cement, concrete or a more or less 
elastic mastic has been shown in many cases, for the excessive 
expansion and contraction resulting from a range of perhaps 
over a hundred degrees in temperature have been the cause of 
almost inevitable rupture. But the difficulty has been success- 
fully overcome by the use of waterproof felt in combination 
with a cementing compound. By similar means, reinforced 
concrete bridges have been rendered impervious to the passage 
of water from the road bed while deterioration and positive 
danger have been shown to result in the case of structures not 
so protected. 

In "cut and cover" construction where the surface to be 
waterproofed is exposed during the building process and sub- 
sequently covered as in the case of some great tunnel under- 
taking the best opportunity is presented for the employment of 
the envelope method. Here the felt and its intermediate coatings 
are readily applied to the exterior surface; inspection of the 
work is simple and reasonably good workmanship is insured. 

But where excavation is necessary for the building of the 
structure which is to be waterproofed the problem becomes 
more involved. Here the manifold shield must be formed in 
advance of the construction which it is to envelop. This is 
usually accomplished by first building against the wall of 
the excavation a light wall of brick or similar material to 
which the fabric forming the shield may be applied. When 
this has been done in a sufficient number of layers in connec- 
tion with the cementing compound the wall of the structure 
itself is built. In this manner the envelope is most logically 
constructed as an enclosure for the structure. 

In driven tunnels entirely beneath the surface the water- 
proofing felt is usually applied to the smoothed walls formed 
in the process of excavation. Within this core or envelope 
the finished walls are then built. 

Manifestly each type of structure requires its special treat- 
ment. Practical illustrations are given in succeeding pages. 

ll 



THE WATERPROOFING OF STRUCTURES 



Certain reasonable risks may be run and experiments tried 
in structures where correction, repairs or changes may subse- 
quently be made without danger or difficulty. But in the case 
of waterproofing it is imperative that no chances be taken; for 
the risk is too great — to make good a bad job may entail an 
expense ten to twenty times its original first cost. Hence only 
the most suitable method and the very best of materials should 
ever be employed. The superior advantages of the envelope 
method having been considered it is but proper that attention 
should next be given to the necessary qualities of a water- 
proofing felt. 

Time was when so called tar paper was the best and in fact 
practically the only material available for use in the then unde- 
veloped practice of waterproofing by the envelope method. 
Before the general advent of wood pulp even the paper used 
for building purposes was of good quality with distinct fibre 
and reasonable strength. The coal tar used for saturation was 
likewise of far higher grade than is employed to-day. It is not 
strange then that work executed years ago with such relatively 
good materials should, where not exposed to unduly destruc- 
tive agencies, be now and then found to be in good condition. 
It is this very fact combined with lack of knowledge of progress 
in the science of waterproofing that still leads some to employ 
the present day materials which pass under the same name. 

But tar paper or coal tar felt is to-day ordinarily a cheap 
material of little strength and less endurance under the search- 
ing requirements of modern waterproofing construction. The 
paper is usually of short fibre, hard and brittle. The coal tar 
used as a saturant has been refined to such a point in order to 
extract the various products which are more valuable for other 
purposes, that the coal tar left and used for saturation is practi- 
cally nothing but a residuum of little value for any purpose. 

The gradual reduction in quality of such material combined 
with the increasing demand for a fabric eminently suited to 
modern requirements has led to the development of various 
fabrics almost universally called "waterproof" although pos- 

12 



THE WATERPROOFING OF STRUCTURES 

sessed of that quality in various degrees. An intermediate 
stage in this development is marked by the attempt to use a 
woven fabric like burlap or similar cheap material as a carrier 
or absorbent for a certain amount of waterproofing compound 
and as a support or conveyer for applied coatings of cementing 
compound. 

Fundamentally the completely vegetable character of such 
material is objectionable for it is possessed of little durability 
when exposed to underground conditions. The fact that it is 
woven still further contributes to its unworthiness ; for unlike 
a uniform fabric similar to felt or even paper its body consists 
of alternate material and interstices. Upon the compound 
employed for saturation and coating therefore falls the burden 
of completely closing these spaces as well as of rendering im- 
pervious the actual material of which the fabric is made. 
What is more, the crossing of the fibres in the warp and woof 
results in an arrangement which entails a readjustment of rela- 
tions the moment the fabric is stretched or twisted; a conse- 
quent change in shape of the individual interstices takes place. 
The result is obvious, — water-tightness cannot be maintained 
except at excessive cost. 

On the other hand a material having the characteristics of 
a felt or paper with the fibres matted together is of the same 
texture throughout; if made of suitable materials it is always 
amply pliable. The minute individual fibres, if properly satu- 
rated, work almost infinitesimally upon each other when the 
material is stretched. The saturant itself fills all pores with 
the result that the felt retains its waterproof character even 
when subjected to great strain and distortion. 

Waterproofness, pliability and durability are obviously the 
prime essentials in such a felt. As in all materials the quality 
of the finished product depends upon the individual qualities 
of its ingredients. The exacting demands made upon a water- 
proofing felt and its relatively small cost as compared with the 
damage which may result from possible inferiority makes it 
imperative that only the very highest grade of materials should 

13 



THE WATERPROOFING OF STRUCTURES 

be used in its manufacture. But the quality of the ingredients, 
even though of the best, does not alone determine the real 
value and efficiency of the product when used for a specific 
purpose. Character and suitability in view of the conditions 
are of equal importance. 

Take the case of wool for instance as one of the substances 
incorporated in the felt. Because of its superiority to other 
available materials, as an absorbent of the saturating compound, 
wool is invaluable in a waterproofing felt. Its percentage 
therefore determines the possible degree of saturation. A well 
made felt is generally most effective as a waterproofing material 
when it contains the amount of suitable saturant which can be 
held by an amount of wool equivalent to from a minimum of 
20 to a maximum of about 30 per cent, of the weight of the 
unsaturated fabric. A lesser amount would leave the felt 
inadequately waterproofed while a greater amount would so 
increase the relative amount of saturating compound as to de- 
crease the strength. Hence it is evident that in a reputable 
fabric even though known asa <( wool felt' ' the proportion of 
wool should average about 25 per cent. 

The balance should be made up of such material as will best 
serve in combination with the wool and the saturant to form 
the most pliable, durable and waterproof fabric. The satura- 
ting and coating compounds should be of a character capable 
of remaining plastic after long heating at a temperature of at 
least 250 degrees and the surface of the felt should not crack 
when bent double at ordinary temperature. 

The saturant employed for such a felt must not only serve 
specifically as insulation against moisture, but it must remain 
unaffected by continued contact with water or dampness, even 
at high or low temperatures, it must not deteriorate with age, 
and must be capable of resisting the chemical action of all 
ordinary agents which may be found in ground waters, escaping 
sewerage and the like, and permit the felt to remain perma- 
nently pliable. In its best form such a compound should be 
a combination of gums and mineral non-volatile oils insoluble 

14 



THE WATERPROOFING OF STRUCTURES 

in water, and should retain some of the properties formerly 
found in coal tar but which are now customarily extracted from 
it before it is used for saturating the cheaper felts. All injurious 
chemicals should be eliminated. 

Many of the so-called waterproofing felts are saturated and 
coated only with common asphalts or tar, which will dry out 
and become brittle, and render the felt worthless. Water- 
proofing is of too much importance to risk the use of such 
methods. 

A suitable felt should be capable of easy application and as 
a matter of importance should have a natural affinity for any of 
the reliable mineral pitches, distillates of straight asphalt or 
straight coal tar, which may be employed for cementing the 
sheets of felt together, in the process of applying the work. 
Only in this way may perfect bonding be assured. In the 
process of saturating it is customary to also leave upon the felt 
a distinct waterproof coat. This must be thoroughly pliable, 
not subject to cracking at low temperatures or liable to become 
too plastic and adhesive at high temperatures. Under normal 
conditions it must of necessity be somewhat "tacky." As a 
result when felt which is coated upon both sides is rolled in the 
usual manner for shipment, it is practically impossible to pre- 
vent the adhesion of the adjacent coated surfaces except by the 
expensive method of separating them by the introduction of 
paper, or by reducing the adhesiveness of one of the surfaces 
by coating it with some substance such as talc or ground wood 
pulp. But when a sufficient amount is applied to prevent ad- 
hesion in the roll the affinity of this coated surface for the hot 
pitch employed in laying the felt in position is very much 
lessened. 

This practical objection is removed when only one side of 
the felt is coated. Then only the minutest amount of talc or 
its equivalent is required to keep the surfaces from adhering in 
the roll. A quarter of a pound per one hundred square feet is 
usually sufficient, in fact the amount is so slight as to be barely 
perceptible. 

15 



THE WATERPROOFING OF STRUCTURES 



But what is more important, it has been conclusively demon- 
strated by experience that better adhesion on the work is se- 
cured between the different plies when only one side is coated. 
The hot pitch which in the process of laying is applied to the 
cement or mortar construction or to the coated side of the felt 
is found to adhere in its rapidly cooling condition much more 
readily to the uncoated surface of a piece of felt pressed against it. 

The explanation appears evident. The compound which is al- 
most universally applied hot begins to cool rapidly, immediately 
after being mopped upon the surface. Although in its hot 
state it is capable of softening a skin coat upon the felt to which 
it is applied and thereby getting a grip upon the texture of the 
material it loses this power when even slightly cooled. It is 
usually in this latter condition when the new sheet is pressed 
upon it, hence the imperfect bond which usually results if this 
sheet is skin coated. But when such coating is absent the com- 
pound is given direct access to the body of the felt and a perfect 
bond is insured with no spots insecurely fastened as is often 
the case with similar material coated on two sides. 

To these marked advantages of felt coated upon one side 
only are added still others of marked importance from a prac- 
tical standpoint. 

By the omission of one coat, the weight is decreased while 
the strength which is practically unaffected by the extra coat, 
remains substantially the same. In other words, a thinner, 
lighter and more pliable felt is secured without impairing its 
strength. Because of its decreased weight it is easier to handle 
and because of the thoroughness of the bond it insures the 
greatest security against dampness, for when cemented together 
with the certainty attendant upon the use of single-coated felt 
the mass consisting of several plies becomes absolutely homo- 
geneous; an impossible barrier for water. The lightness of this 
felt materially facilitates its use, for work may be carried on more 
expeditiously and with greater certainty of satisfactory results. 

Of especial advantage is this feature in the waterproofing of 
a vertical wall. With ordinary felt coated upon both sides the 

16 



THE WATERPROOFING OF STRUCTURES 

effect of the already applied hot compound is, as already indi- 
cated, to simply soften up the skin coat of the first sheet and 
to a lesser degree that of the second sheet which is pressed 
against it. The whole mass then remains in a semi-fluid 
condition, for the compound used to cement the sheets together 
remains plastic for some time. As a result of the presence of 
this excess of viscous material between the sheets the second 
sheet has a strong tendency to slide off of the first unless it is 
securely held in place for some time by means of a heavy 
weight laid on the sheets where they are turned over the top 
of the wall. During this period it must be firmly pressed 
against the wall by an elaborate system of planks and braces. 

Practically all of this annoyance is avoided and certainty of 
bond is assured when the felt is coated on one side only. Not 
only is a bond more quickly and securely made by pressing 
the uncoated side against the cementing compound, but the 
sliding motion may thus be retarded, while the lessened weight 
of the felt greatly reduces the pull. 

The weight of a reliable wool felt before saturation should 
be from 5 to 7 pounds per 100 square feet. When saturated and 
coated one side it should weigh roughly from 12 to 14 pounds 
per 100 square feet, while the weight of a similar area saturated 
and coated on both sides should range from about 14 to over 
16 pounds. 



17 



THE WATERPROOFING OF STRUCTURES 




APPLICATION OF TUNALOID 



PENNSYLVANIA TUNNEL & TERMINAL RAILROAD COMPANY S 
IMPROVEMENTS, NEW YORK AND SUNNYSIDE, LONG ISLAND 



THE WATERPROOFING OF STRUCTURES 



Tunaloid and Its Application 

r I ^HIS somewhat extended but nevertheless very necessary 
-■- consideration of the conditions of sub-level construction; 
the various methods of preventing the entrance of water and 
the requisites of materials to be used in the application of the 
envelope method cannot fail to emphasize the fact that a satis- 
factory waterproof felt or a suitable compound is not the 
creation of a day. Such materials are not brought to perfec- 
tion except as the result of expert knowledge, long experiment, 
and thorough trial under exacting conditions. 

For, generations J. A. & W. Bird & Co. have been de- 
signers and manufacturers of waterproofing materials, felts, 
compounds, roofing, etc. For years, experiments have been 
conducted to determine the efficiency and endurance of mate- 
rials for the waterproofing of sub-level construction, where the 
entrance of water under heavy pressure must be resisted. 
The result is represented by " Tunaloid Waterproof Felt," 
"Tunaloid Compound," and "Tunaloid Damp- Proof Paint." 
With these three materials a complete structure may be 
thoroughly protected. The name " Tunaloid " was bestowed 
because of the primary use of the felt in connection with tunnel 
construction where the most difficult of all conditions were 
encountered and overcome. What Tunaloid has there accom- 
plished, it may be relied upon to accomplish elsewhere under 
less adverse conditions. 

Tunaloid Waterproof Felt is essentially a wool felt, tough 
and fibrous, and containing the suitable quantity of wool to 
secure and maintain the proper balance between strength of 
felt and degree of saturation. It has already been shown that 
too much wool is as detrimental as too little. The saturant 
likewise conforms to the requirements of the resistance to the 
effect of water or chemicals present in the soil, to enduring 

19 



THE WATERPROOFING OF STRUCTURES 




APPLICATION OF TUNALOID 

PENNSYLVANIA TUNNEL & TERMINAL RAILROAD COMPANY'S 
IMPROVEMENTS, NEW YORK AND SUNNYSIDE, LONG ISLAND 



THE WATERPROOFING OF STRUCTURES 

plasticity which constantly maintains the pliability of the felt, 
and to its easy manipulation without sticking. In fact it em- 
bodies every quality obtainable in the highest grade material. 

In the manufacture of Tunaloid, the use of tar in any form 
as a saturant has been avoided. The saturating compound 
which is made up specifically for insulation against water or 
moisture is a combination of gums and mineral non-volatile 
oils, and retains some of the properties which were formerly 
found in coal tar, but which are now extracted from it before 
it is used in saturating the so-called tar felts. In fact the mate- 
rial ordinarily used is nothing more than a residuum having 
little value for any purpose. In the compound used for sat- 
urating Tunaloid the injurious chemicals have been extracted 
and others added so as to secure the most lasting and durable 
results with the very highest insulating properties obtainable. 
Special attention has been paid to retaining the properties which 
have an affinity for the good and reliable qualities of mineral 
pitches, and particularly of Tunaloid Compound which may 
be used as a cementing medium. The result of this careful 
selection and preparation of materials is a felt of highly superior 
quality which under experimental test as well as in regular 
practice remains uniformly waterproof. Many tests have been 
made upon Tunaloid which confirm this statement. Among 
these are those conducted at the University of Wisconsin by 
Professor F. M. McCullough, who makes the following report 
on waterproofing tests of Tunaloid and tar. 

"Four 6-in. pipes, 12 in. long, were filled with 1:3:5 con- 
crete October 25, 1909. These specimens were waterproofed 
November 12, 1909, in the following manner. A coat of hot 
tar was applied to the upper surface of the concrete; a sheet 
of Tunaloid was now placed on this tarred surface and care- 
fully smoothed down with the hands. Alternate layers of tar 
and Tunaloid were applied in the same way until the speci- 
mens were covered with three thicknesses of Tunaloid and 
four layers of tar. The rough and skin coated surfaces of the 
Tunaloid were always placed together. On November 30 

21 



THE WATERPROOFING OF STRUCTURES 




APPLICATION OF TUNALOID 

PENNSYLVANIA TUNNEL & TERMINAL RAILROAD COMPANY'S 
IMPROVEMENTS, NEW YORK AND SUNNYSIDE, LONG ISLAND 



22 



THE WATERPROOFING OF STRUCTURES 



the specimens were attached to the permeability apparatus and 
for the next 1 1 days the waterproofed surfaces of the specimens 
were subjected to pressures of water varying from 38 to 40 
pounds per square inch. The waterproofing gave very sat- 
isfactory results as the specimens showed no flow whatever 
during this period." 

But the distinctive feature of Tunaloid, which differentiates 
it from all felts, lies in the coating of one side only. The dis- 
advantages of a felt coated upon both sides have already been 
presented. In Tunaloid these are avoided. Only the most 
minute dusting with talc is necessary to keep the adjacent sur- 
faces (one coated and one uncoated) from sticking together 
when the felt is tightly rolled. As a consequence there is no 
resistance by the dusted surface to the ready entrance of the 
cementing compound when the felt is applied to the work. 
But of far greater importance, as the result of leaving one side 
uncoated, is the readiness with which this cementing com- 
pound, in its rapidly cooling condition enters into the very 
pores of the fabric, absolutely insuring thorough adhesion be- 
tween the successive layers of felt as they are laid. Tunaloid 
is the thinnest waterproof felt made, but its tensile strength is 
equal to that of the heaviest felt. 

The method of coating Tunaloid on one side only is of very 
great advantage to the user. Not only does it enable him to 
carry out his work more expeditiously, but it is an undisputable 
fact that a much better bond between the two sheets is secured 
than in the case of a waterproofing felt coated on both sides. 

As the omission of the coating on one side reduces the weight 
of the felt, so also does it increase the facility with which it may 
be handled, particularly on vertical wall surfaces. The general 
method of application of Tunaloid Waterproof Felt and 
Tunaloid Compound is made clear by the accompanying illus- 
trations and succeeding notes regarding the same : 

It is always laid in several plies or layers so as to cover all 
parts of the surface with from two to ten thicknesses. To 
secure the best results it must be "shingled;" that is, each 

23 



THE WATERPROOFING OF STRUCTURES 




APPLICATION OF TUNALOID 



PENNSYLVANIA TUNNEL & TERMINAL RAILROAD COMPANY S 

IMPROVEMENTS, NEW YORK AND SUNNYSIDE, LONG ISLAND 

24 



THE WATERPROOFING OF STRUCTURES 

strip or width must overlay the next adjacent strip. The proc- 
ess may be described as follows : 

First, all of the surface to be waterproofed must be made 
thoroughly smooth if necessary by the application of cement 
mortar, and this must be allowed to become thoroughly dry 
before the cementing compound is applied. This compound, 
thoroughly heated, is applied with a mop and the felt im- 
mediately rolled over the surface. Where it is possible several 
rolls should be started at once and the cementing compound 
swabbed on the surface ahead so that there is the least possi- 
ble loss of time in covering it with the felt and pressing the 
same into position. 

The first roll having been started and mopped, the second 
is placed so as to overlap the first by a width, depending upon 




APPLICATION OF TUNALOID 



PENNSYLVANIA TUNNEL & TERMINAL RAILROAD COMPANY S 

IMPROVEMENTS, NEW YORK AND SUNNYSIDE, LONG ISLAND 

25 



THE WATERPROOFING OF STRUCTURES 




PENNSYLVANIA TUNNEL & TERMINAL RAILROAD COMPANY S 

IMPROVEMENTS, NEW YORK AND SUNNYSIDE, LONG ISLAND 

WATERPROOFED WITH TUNALOID 

the number of plies to be laid. For instance, if the felt is 32 
inches wide and it is to be laid 6-ply the lap of the second roll 
over the edge of the first will be about 26^ inches or five 
sixths of the width. As soon as the second roll has been 
sufficiently unrolled to allow space, the third roll is started so 
as to lap both of the others. This process with the corres- 
ponding mopping is continued for the entire width of the sur- 
face which is to be covered. The result is a homogeneous mass 
having equal thickness and strength throughout, forming an 
impassable barrier to water and possessing a degree of pliability 
which enables it to yield to distortion of the structure to which 
it is applied. 

The numbers of layers or plies required for any given 
structure must depend upon the existing conditions. Specific 
tabulation for different depths is apt to be somewhat mislead- 
ing because of the varying conditions of structure, soil, etc. 
For work extending but a few feet below the surface three or 
four plies will almost always serve to insure adequate protec- 



THE WATERPROOFING OF STRUCTURES 

tion, but for most work running deeper than this at least five 
or six plies will be required. 

In the use of Tunaloid Waterproof Felt the uncoated side 
of the sheet is always pressed into the coating of the cement- 
ing compound. This leaves the coated side of the sheet ex- 
posed to view. The hot compound which is applied to this 
surface softens and combines with the coating on the felt so 
that it is not difficult to get a firm grip on the next sheet of 
which the uncoated side is pressed against the film of cement- 
ing compound. But before the second and succeeding sheets 




PENNSYLVANIA TUNNEL & TERMINAL RAILROAD COMPANY S 

IMPROVEMENTS, NEW YORK AND SUNNYSIDE, LONG ISLAND 

WATERPROOFED WITH TUNALOID 



can be laid one upon another, the compound which separates 
them is bound to cool because of its contact with the colder 
surface of the under sheet or the walls of the structure. As 
a result the compound which has been mopped upon the sur- 
face becomes slightly glazed over. It therefore tends to resist 
adhesion to a somewhat similar hard coated surface on a piece 

27 



THE WATERPROOFING OF STRUCTURES 

of felt, but in the case of Tunaloid this coating is lacking, and 
the fibrous surface of the uncoated side presents a far better 
opportunity for the rapidly cooling compound to take hold 
and bite in to the fibre. This simple difference between Tun- 
aloid and other felts is a most vital feature in its successful use. 
The instantaneous adhesion which results from this condition 
very much simplifies the application of felt waterproofing to a 
vertical wall. The fact that the uncoated surface has not been 
dusted with material to prevent its adhesion within the roll as 
is necessary with felt coated on two sides materially increases 
the ease with which the cementing compound penetrates the 
surface. As already indicated the lightness of Tunaloid felt is 
an important factor in the readiness of handling it upon verti- 
cal walls. In the case of heavier felts coated on both sides it is 
necessary to provide sufficient means to prevent their sliding 




PENNSYLVANIA TUNNEL & TERMINAL RAILROAD COMPANY S 
IMPROVEMENTS, NEW YORK AND SUNNYSIDE, LONG ISLAND 

WATERPROOFED WITH TUNALOID 



THE WATERPROOFING OF STRUCTURES 

off when first applied. This naturally results from laying two 
skin coated surfaces of felt together with a viscous substance 
like the cementing compound between them, but when the 
uncoated side of a sheet of Tunaloid is applied to the coated 
side of the preceding sheet of the same material which has been 
treated with a hot compound, the two sheets become thor- 
oughly amalgamated and the outer sheet is readily supported 
by adhesion. In fact the Tunaloid method provides sufficient 
and only sufficient binding material to securely and permanently 
hold the two sheets together. 

Experience shows that a hot cementing compound takes hold 
better and penetrates further than one that is applied cold; as 
a result, a better bond between the sheets is secured. Condi- 
tions must determine the exact character of the compound. 
Broadly speaking, a satisfactory compound should soften at 
ordinary atmospheric temperatures and melt at about 100 de- 
grees F. It should contain such a proportion of oils as may 
be essential to giving it elasticity and long life. So far as pos- 
sible it should stand great extremes of temperature and should 
retain its cementing qualities under all conditions, not becom- 
ing hard and brittle at low temperature, or too fluid at high 
temperature. These characteristics distinguish Tunaloid Com- 
pound which has been carefully developed by experiment to 
serve as the most suitable material for cementing together the 
sheets of Tunaloid Waterproof Felt. 

Most of the accompanying illustrations clearly indicate with- 
out further explanation the location and in general the method 
of application of Tunaloid Waterproofing Felt. The selec- 
tion of photographs of actual work has been intentionally re- 
stricted with a few exceptions to those taken upon a single 
large undertaking, namely, the improvements made by the 
Pennsylvania Tunnel & Terminal Railroad Co., at New York 
and Sunnyside, Long Island. This covers a wide diversity of 
construction both underground and overhead. This work 
alone required the use of over 9,000,000 square feet of 
Tunaloid Waterproof Felt. 

29 



THE WATERPROOFING OF STRUCTURES 




tf "'**- 


"^•f^-Vf- - 


JB — --, 


J— ^ 


2 







APPLICATION OF TUNALOID TO THE EXTERIOR OF A CONCRETE 
TUNNEL WITH VERTICAL WALLS 



THE WATERPROOFING OF STRUCTURES 




APPLICATION OF TUNALOID TO THE EXTERIOR OF AN ARCHED 

CONCRETE TUNNEL 

31 



THE WATERPROO FING OF ST RUCTURES 

The groups of successive photographs shown upon the two 
preceding pages make quite clear the method of applying Tun- 
aloid on the tunnels which form a large proportion of the con- 
struction in connection with the previously mentioned improve- 
ments. In both cases the surfaces to be waterproofed were ex- 
posed and easily accessible. All construction was of con- 
crete and all waterproofing felt was protected by an exterior 
or armor course of brick or cement. By following through 
these illustrations in the order of their numbers the progressive 
steps in the application of Tunaloid may be made clear. 

In case of the tunnel with vertical walls the free end of a 
roll of felt was lowered to the ground with the uncoated sur- 
face of the felt next to the wall which had already been thor- 
oughly mopped with cementing compound. The roll itself 
was held from above and the felt at once securely pressed 
against the vertical wall. The practically horizontal top of the 
tunnel was then mopped and the felt unrolled toward the other 
side, as shown in the second cut. In the succeeding cuts the 
roll is shown as being still further unrolled on the other verti- 
cal side until it finally reaches the ground and is pressed against 
the surface which has been mopped in advance of its descent. 
This felt was all laid 6-ply. 

As the work progressed, the waterproofing on the top of the 
tunnel was permanently protected by a single course of brick, 
or in some cases by a somewhat less thickness of concrete. 
The waterproofing upon the sides was protected by a single 
thickness wall of brick extending to the top. 

In the case of the arched concrete tunnel the felt in succes- 
sive rolls was started from the top and unrolled over the freshly 
mopped surface until it reached ground level. Other rolls fol- 
lowed in succession so as to secure a homogeneous 6-ply en- 
velope or shield with suitable laps. In all cases the rolls were 
started with the uncoated sides toward the concrete so that the 
outer surface of the finished envelope presented the coated 
side of the felt, which was given a final mopping. All of this 
work was protected by one course of brick laid over the arch. 

32 



THE WATERPROOFING OF STRUCTURES 



The accompanying cross sectional drawings of single and 
twin-tunnels clearly indicate the methods employed for water- 
proofing with Tunaloid some of the sublevel work which 
formed a part of the improvements undertaken in New York 
City by the Pennsylvania Tunnel & Terminal Railroad Co. 
The single arch type here shown with a heavy brick arch, was 
constructed in tunnel; in the open cut sections the roof was of 
concrete. Both were completely waterproofed with Tunaloid 
on the invert, roof and sides ; in the tunnel sections the space 




CROSS SECTION OF TUNNEL WATERPROOFED WITH TUNALOID 
PENNSYLVANIA TUNNEL & TERMINAL RAILROAD COMPANY'S IMPROVEMENTS, NEW YORK 

above the brick roof was filled with rock packing. Six thick- 
nesses of felt and seven of cementing compound were laid 
upon the invert and sand-walls and carried entirely around the 
extrados of the arch, thus forming a complete envelope. 

In laying the brick the courses of the ring were carried up 
as high as the void between the extrados and the rock would 
permit and still leave a working space in which to place the 
waterproofing. This was laid for that height, joined to the pre- 
vious waterproofing on the side walls and followed by the brick 
armor course over the waterproofing and finally by the rock 
packing. 

33 



THE WATERPROOFING OF STRUCTURES 



The plans originally contemplated the use of a complete 
concrete lining in the twin-tunnels except where large quan- 
tities of water were encountered, in which cases the arches, 
beginning at about IS degrees above the springing line, were 
to be built of vitrified brick. The waterproofing was then 
carried completely over the arch. In the construction of twin 
tunnels entirely of concrete the waterproofing was similarly 
carried up the sand walls and then over the extrados as fast as 
the concrete was laid and then protected by an armor course 
of concrete. 

'■*&}#% . ROCK ■■ . ._, , 




CROSS SECTION OF TWIN TUNNELS WATERPROOFED WITH TUNALOID 
PENNSYLVANIA TUNNEL & TERMINAL RAILROAD COMPANY'S IMPROVEMENTS, NEW YORK 

On all work the joints of felt were lapped at least one foot 
and when work was suspended for a time and a bevel lap could 
not be made the edges of the felt were left uncoated with com- 
pound and the newer work subsequently interlaced with the old. 

The application of Tunaloid to various types of construction 
at the Sunnyside improvements is so comprehensively shown 
by the preceding photographs that no particular description of 
methods appears to be necessary. Practically all of the work 
was done in open cut or well above ground level and was there- 
fore lacking in most of the difficulties of the construction just 
described. 



THE WATERPROOFING OF STRUCTURES 




KINGSLAND CAR SHOPS, DELAWARE, LACKAWANNA & WESTERN 
RAILROAD, KINGSLAND, N. J. 

The following illustrations of waterproofing with Tunaloid 
done in connection with sublevel work at the Kingsland car 
shops of the Delaware, Lackawanna & Western Railroad, at 
Kingsland, N. J., show very clearly the manner of treating 
such work. In connection with the power plant at these 
shops there was planned an extended system of relatively small 
tunnels for steam pipes, electric wires, etc. These were located 
only just below ground level, and were somewhat complicated 
in form, as is evident from the accompanying illustrations. 
They were all made of concrete, the Tunaloid waterproof felt 
covering the tops and sides of those extending between build- 
ings. Drains were laid beneath these tunnels so that thorough 
drainage of the surrounding soil was insured and opportunity 
provided for the escape of any water which might collect 
within the tunnel. For this reason it was not necessary to 
waterproof its bottom in the case of tunnels in the open yard. 

35 



THE WATERPROOFING OF STRUCTURES 



T— — : 



^wm 







APPLICATION OF TUNALOID TO STEAM PIPE AND 
ELECTRIC WIRE SUBWAY 




APPLICATION OF TUNALOID TO ASH TUNNEL AND STEAM PIPE AND 
ELECTRIC WIRE SUBWAY. 



SUBWAY CONSTRUCTION, KINGSLAND CAR SHOPS, DELAWARE, LACKA- 
WANNA & WESTERN RAILROAD, KINGSLAND, N. J. 



36 



THE WATERPROOFING OF STRUCTURES 



■ — - But in the case of 

the parallel ash and 
i^-: Z^' : 'r--\:\r-i'-i---\^-^^'^t&.t^ steam tunnels be- 
neath the power house 
felt was carried entirely 
beneath, and the walls 
of the concrete con- 
struction thus com- 
;k.:; pletely enveloping it. The 
depth being comparatively 
slight and the opportunity 
remote for the pocketing of 
water, only 4-ply of Tunaloid 
was required on any of this 




work. 



APPLICATION OF TUNALOID TO SUBWAY 
D., L. & \V. R. R. 



The universal applicability of the envelope method of water- 
proofing can hardly be better indicated than by the accompany- 
ing cross sections of more or less irregular subway construction. 
In each case the felt completely surrounds the concrete structure. 
When the difficulties encountered in building a subway in the 
congested streets of a city are considered, it must be manifest 
that the envelope or exterior method would not be employed, 
in place of applications to the inner walls unless it was deemed 




METHOD OF APPLYING WATERPROOFING FELT TO SUBWAY 
37 



THE WATERPROOFING OF STRUCTURES 




far more reliable. 

The manner of ap- 
plying the felt and 
carrying it up over 
the top of the subway 
must of necessity be 
influenced by the 
conditions of con- 
struction, for seldom 

* IRREGULAR SHAPED SUB- 

is it possible to make way waterproofed by 
a clear cut and build THE envelope method 
up the work as a unit. 

If it is done piecemeal so also must be the waterproofing, 
but the interlacing of thicknesses of felt simplifies the joining 
of new work to old. No general method of construction can 
be established for such work, for variations must be made even 
after all plans are completed to meet unexpected conditions. 
The street may be excavated only enough to allow the roof 
beams to be set in position from side wall to side wall and the 
roof finished first. The core may then be excavated under- 
neath. Or the side walls may be entirely completed before the 
floor or invert is laid. Shoring of adjacent building walls may 
be necessary or the new tunnel may displace an old sewer. In 

such case it may be 
necessary to first 
build the side walls 
containing new sew- 
ers into which the 
sewage must first be 
turned. Nevertheless 
the entire structure 
may be successfully 
enveloped in multiple 
layers of felt and the 

COMPLETE ENVELOPE OF WATERPROOF FELT aUlTHSSlOn Ol Water ei- 

around subway fectually prevented. 

38 




THE WATERPROOFING OF STRUCTURES 

If waterproofing is necessary in such comparatively rough 
underground structures as have already been described, mani- 
festly it is imperative in the case of a building with fine interior 
finish. It is not the purpose here to either illustrate or de- 
scribe in detail the various applications of Tunaloid Waterproof 
Felt to foundation walls. It is merely sufficient to point out 
the general features of the method. Of course the simplest 
application is in the case of walls, the outside of which are 
exposed, and to which the felt may be readily applied. But 
such conditions are comparatively rare, for their very existence 
suggests that waterproofing is not required. 

But where excavation is deep and access cannot be had to the 
outside of the walls after they are built, the envelope is readily 
formed of felt prior to the construction of the foundation. As 
this envelope should always be protected from damage on the 
outside, two purposes are served when a thin wall of brick or 
concrete is laid up just inside of the excavation. If this is in 
earth which is held back by sheeting, the problem is easily solved. 
If, on the other hand, the excavation is in rock the preparation 
of a smooth surface will depend upon the irregularity of the rock 
surface. To this finished surface the felt is applied in the 
requisite number of layers with alternate coatings, and the 
lower end is turned in toward the building so that the founda- 
tion rests upon it. To give double assurance of tightness the 
intersection of vertical wall and footings may be tongued and 
grooved lengthwise of the wall and the felt carried over the 
projection thus formed. From the wall it may be extended 
inward so as to protect the entire basement floor if so desired. 
Frequently the opportunity for drainage is such that there may 
be no upward effort of the water to gain entrance through the 
floor. But where the basement is below water level, provision 
for thorough waterproofing must be made by carrying the felt 
as an envelope underneath the entire upper course of the floor, 
which may be of brick or concrete, or a combination of both. 
The general method of applying waterproof felt to a foundation 
wall and basement floor is typically illustrated herewith. 



THE WATERPROOFING OF STRUCTURES 



The purpose of waterproofing the base- 
ment floor is obviously to prevent water 
coming up through it, but it may be de- 
sired to waterproof the upper floors so as 
to prevent water coming down through 
them in case of fire or leakage. The 
same methods of application of Tunaloid 
which have been described elsewhere may 
be employed here with assurance of per- 
manent tightness. 

In the waterproofing of all such struc- 
tures especial care and critical supervision 
must be exercised to avoid accidental or 
intentional puncturing of the envelope. 
This is most liable to occur through the 
acts of irresponsible workmen who may 
be charged with placing of pipes and 
wires. The openings which are thus 
made, either through necessity or acci- 
dent, must be carefully repaired by those 
who are competent. 

The method of applying Tunaloid to a bridge is indicated by 
the accompanying sections. This felt, usually in about six 
courses, is laid upon the reinforced concrete of the arch and 
protected above by a course of brick or cement. Upon this 
the ballast is filled, in which the ties are laid. Proper drain- 
age is provided by pitching the upper surface of the concrete 
and attached waterproofing toward drainage holes located at 
regular longitudinal intervals. Absolute protection is furnished 




METHOD OF WATERPROOF- 
ING BASEMENT FLOOR AND 
FOUNDATION WALLS 




mramoorM f£ir. 



METHOD OF WATERPROOFING A RAILROAD BRIDGE 
40 



THE WATERPROOFING OF STRUCTURES 

to the concrete, seepage is prevented and the come and go due 
to extremes of temperature is provided for by the pliability of 
the felt. 









1 


1 






























'? . 


mF ; - ; 




jmrt'' 1 1* 11 . 


..,__ 




W&^* 


w&jfr*. 










Wpj:" 


77 -^ 











LAUREL HILL BRIDGE, PENNSYLVANIA & TERMINAL RAILROAD IM- 
PROVEMENTS, SUNNYSIDE, LONG ISLAND. WATERPROOFED 
BENEATH TRACKS WITH 6-PLY TUNALOID 

Manifestly Tunaloid finds a place for usefulness wherever 
water is to be prevented from passing. But the illustrations 
and descriptions already presented are undoubtedly sufficient 
to indicate in a general way the method to be employed in any 
case. But waterproofing of this character may be just as essen- 
tial as the means of keeping water within a structure as keeping 
it out. Thus Tunaloid is employed for rendering impervious 
cisterns, tanks and pumping chambers. 

The increasing recognition of the effect of moisture upon 
the steel reinforcement embedded in concrete is attracting 
attention to the necessity of thoroughly waterproofing all such 
portions of a structure as may be exposed to water. Of still 
greater importance is the waterproofing of structural steel which 
is not protected by concrete, but exposed to water. This is 
readily accomplished by the envelope method. 



THE WATERPROOFING OF STRUCTURES 



Tunaloid 
Damp-Proof Paint 

TT has been made evident that wherever external water 
■*• exists, as is usually the case in connection with suhlevel 
work, the envelope or shield method is essential and that 
Tunaloid Waterproof Felt is an unexcelled material for form- 
ing the envelope. But where the depth below the surface is 
slight and the soil is comparatively dry, or where the super- 
structure or the interior walls are to be protected against the 
normal passage of moisture, such material or method is not 
ordinarily necessary, and the requirements may be met by a 
properly compounded paint. Such is Tunaloid Damp-Proof 
Paint which has been "designed" so to speak, to meet the 
exacting requirements. Partaking of some of the character- 
istics of the saturant in Tunaloid Waterproof Felt and of 
Tunaloid Compound, this paint combines all of the quali- 
ties essential to the protection of masonry surfaces exposed to 
moisture. 

Tunaloid Damp-Proof Paint is a thick black liquid com- 
pound from selected gums melted into a uniform mass and 
without pores. 

When applied, it forms an elastic film over brick, concrete 
or similar surfaces, thereby closing the pores and excluding 
moisture or dampness from striking through. It is elastic 
under all and any conditions and of a tacky consistency. 

The more or less porous condition of concrete, mortar, 
brick or terra-cotta, or similar materials, presents an oppor- 
tunity for the absorption of paint applied to their surface, 
rendering difficult successful covering with a waterproof film. 

What is more, the chemical action of the lime and other in- 
gredients of cement is such that all ordinary paints are affected 
and often disintegrate. To offset these difficulties and pre- 
pare a compound that will successfully protect and endure 
without excessive waste of material is manifestly no easy task. 

42 



THE WATERPROOFING OF STRUCTURES 



Tunaloid Damp- Proof Paint is an evenly flowing liquid 
which can be readily applied with a brush. In each case all 
loose dirt, shavings or foreign substance should be removed 
from the surface to be painted. All joints should be thor- 
oughly and carefully pointed up and no open spaces or cracks 
should be left between the bricks. 

On smooth surfaces where there are no deep pores, one 
coat will as a rule be sufficient (unless the conditions are very 
severe). In the case with rough brick or rough concrete, 
two coats should be applied, the first coat being well slapped 
into the pores with a brush, so that every minute hole in the 
surface will be thoroughly filled with the damp-proof paint. 

On foundations, where the dampness is quite excessive, we 
recommend applying Tunaloid Damp-Proof Paint to the out- 
side wall. 

On work above ground or in a basement, where the damp- 
ness is not excessive, the inside of the exposed wall may be 
painted with one or two coats, no part of the wall being left 
untreated. The surface should be gone over carefully and 
retouched where necessary, in order that the coating shall be 
uniform. Paint between beams and window-casings, and 
openings at window-casings should be filled. 

One or two coats of Tunaloid Damp-Proof Paint will be 
required according to the character of the walls and their 
location. 

A complete unbroken film must entirely coat the surface to 
be covered, and this requirement is essential to success. 

Water and dampness will find their way through the small- 
est pin-holes. Therefore, a thorough coating is required. 

Note Carefully. — A wall that is full of dampness should 
never be painted on the outside and inside as well, as in that 
case the dampness is confined in the wall, with no means to 
escape, and will always dry out towards the heat, thus forcing 
off any paint which may be applied to that side. An oppor- 
tunity for the dampness to dry out from a saturated wall must 
always be given. \ r > - 

"■••• 43 



MAR 5 1910 



LIBRARY OF CONGRESS 



021 600 978 2 



